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mempolicy: create mempolicy_operations structure
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Create a mempolicy_operations structure that currently points to two
functions[*] for the various modes:

	int (*create)(struct mempolicy *, const nodemask_t *);
	void (*rebind)(struct mempolicy *, const nodemask_t *);

This splits the implementation for the various modes out of two large
functions, mpol_new() and mpol_rebind_policy().  Eventually it may be
beneficial to add additional functions to accomodate the existing switch()
statements in mm/mempolicy.c.

 [*] The ->create() function for MPOL_DEFAULT is currently NULL since no
     struct mempolicy is dynamically allocated.

[Lee.Schermerhorn@hp.com: fix regression in the package mempolicy regression tests]
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Eric Whitney <eric.whitney@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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David Rientjes authored and Linus Torvalds committed Apr 28, 2008
1 parent 1d0d268 commit 3701294
Showing 1 changed file with 140 additions and 93 deletions.
233 changes: 140 additions & 93 deletions mm/mempolicy.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -63,7 +63,6 @@
grows down?
make bind policy root only? It can trigger oom much faster and the
kernel is not always grateful with that.
could replace all the switch()es with a mempolicy_ops structure.
*/

#include <linux/mempolicy.h>
Expand Down Expand Up @@ -110,8 +109,13 @@ struct mempolicy default_policy = {
.policy = MPOL_DEFAULT,
};

static const struct mempolicy_operations {
int (*create)(struct mempolicy *pol, const nodemask_t *nodes);
void (*rebind)(struct mempolicy *pol, const nodemask_t *nodes);
} mpol_ops[MPOL_MAX];

/* Check that the nodemask contains at least one populated zone */
static int is_valid_nodemask(nodemask_t *nodemask)
static int is_valid_nodemask(const nodemask_t *nodemask)
{
int nd, k;

Expand Down Expand Up @@ -144,125 +148,151 @@ static void mpol_relative_nodemask(nodemask_t *ret, const nodemask_t *orig,
nodes_onto(*ret, tmp, *rel);
}

static int mpol_new_interleave(struct mempolicy *pol, const nodemask_t *nodes)
{
if (nodes_empty(*nodes))
return -EINVAL;
pol->v.nodes = *nodes;
return 0;
}

static int mpol_new_preferred(struct mempolicy *pol, const nodemask_t *nodes)
{
if (!nodes)
pol->v.preferred_node = -1; /* local allocation */
else if (nodes_empty(*nodes))
return -EINVAL; /* no allowed nodes */
else
pol->v.preferred_node = first_node(*nodes);
return 0;
}

static int mpol_new_bind(struct mempolicy *pol, const nodemask_t *nodes)
{
if (!is_valid_nodemask(nodes))
return -EINVAL;
pol->v.nodes = *nodes;
return 0;
}

/* Create a new policy */
static struct mempolicy *mpol_new(unsigned short mode, unsigned short flags,
nodemask_t *nodes)
{
struct mempolicy *policy;
nodemask_t cpuset_context_nmask;
int localalloc = 0;
int ret;

pr_debug("setting mode %d flags %d nodes[0] %lx\n",
mode, flags, nodes ? nodes_addr(*nodes)[0] : -1);

if (mode == MPOL_DEFAULT)
return (nodes && nodes_weight(*nodes)) ? ERR_PTR(-EINVAL) :
NULL;
return NULL;
if (!nodes || nodes_empty(*nodes)) {
if (mode != MPOL_PREFERRED)
return ERR_PTR(-EINVAL);
localalloc = 1; /* special case: no mode flags */
}
policy = kmem_cache_alloc(policy_cache, GFP_KERNEL);
if (!policy)
return ERR_PTR(-ENOMEM);
atomic_set(&policy->refcnt, 1);
cpuset_update_task_memory_state();
if (flags & MPOL_F_RELATIVE_NODES)
mpol_relative_nodemask(&cpuset_context_nmask, nodes,
&cpuset_current_mems_allowed);
else
nodes_and(cpuset_context_nmask, *nodes,
cpuset_current_mems_allowed);
switch (mode) {
case MPOL_INTERLEAVE:
if (nodes_empty(*nodes) || nodes_empty(cpuset_context_nmask))
goto free;
policy->v.nodes = cpuset_context_nmask;
break;
case MPOL_PREFERRED:
policy->v.preferred_node = first_node(cpuset_context_nmask);
if (policy->v.preferred_node >= MAX_NUMNODES)
goto free;
break;
case MPOL_BIND:
if (!is_valid_nodemask(&cpuset_context_nmask))
goto free;
policy->v.nodes = cpuset_context_nmask;
break;
default:
BUG();
}
policy->policy = mode;
policy->flags = flags;
if (mpol_store_user_nodemask(policy))
policy->w.user_nodemask = *nodes;
else
policy->w.cpuset_mems_allowed = cpuset_mems_allowed(current);

if (!localalloc) {
policy->flags = flags;
cpuset_update_task_memory_state();
if (flags & MPOL_F_RELATIVE_NODES)
mpol_relative_nodemask(&cpuset_context_nmask, nodes,
&cpuset_current_mems_allowed);
else
nodes_and(cpuset_context_nmask, *nodes,
cpuset_current_mems_allowed);
if (mpol_store_user_nodemask(policy))
policy->w.user_nodemask = *nodes;
else
policy->w.cpuset_mems_allowed =
cpuset_mems_allowed(current);
}

ret = mpol_ops[mode].create(policy,
localalloc ? NULL : &cpuset_context_nmask);
if (ret < 0) {
kmem_cache_free(policy_cache, policy);
return ERR_PTR(ret);
}
return policy;
}

static void mpol_rebind_default(struct mempolicy *pol, const nodemask_t *nodes)
{
}

static void mpol_rebind_nodemask(struct mempolicy *pol,
const nodemask_t *nodes)
{
nodemask_t tmp;

if (pol->flags & MPOL_F_STATIC_NODES)
nodes_and(tmp, pol->w.user_nodemask, *nodes);
else if (pol->flags & MPOL_F_RELATIVE_NODES)
mpol_relative_nodemask(&tmp, &pol->w.user_nodemask, nodes);
else {
nodes_remap(tmp, pol->v.nodes, pol->w.cpuset_mems_allowed,
*nodes);
pol->w.cpuset_mems_allowed = *nodes;
}

free:
kmem_cache_free(policy_cache, policy);
return ERR_PTR(-EINVAL);
pol->v.nodes = tmp;
if (!node_isset(current->il_next, tmp)) {
current->il_next = next_node(current->il_next, tmp);
if (current->il_next >= MAX_NUMNODES)
current->il_next = first_node(tmp);
if (current->il_next >= MAX_NUMNODES)
current->il_next = numa_node_id();
}
}

static void mpol_rebind_preferred(struct mempolicy *pol,
const nodemask_t *nodes)
{
nodemask_t tmp;

/*
* check 'STATIC_NODES first, as preferred_node == -1 may be
* a temporary, "fallback" state for this policy.
*/
if (pol->flags & MPOL_F_STATIC_NODES) {
int node = first_node(pol->w.user_nodemask);

if (node_isset(node, *nodes))
pol->v.preferred_node = node;
else
pol->v.preferred_node = -1;
} else if (pol->v.preferred_node == -1) {
return; /* no remap required for explicit local alloc */
} else if (pol->flags & MPOL_F_RELATIVE_NODES) {
mpol_relative_nodemask(&tmp, &pol->w.user_nodemask, nodes);
pol->v.preferred_node = first_node(tmp);
} else {
pol->v.preferred_node = node_remap(pol->v.preferred_node,
pol->w.cpuset_mems_allowed,
*nodes);
pol->w.cpuset_mems_allowed = *nodes;
}
}

/* Migrate a policy to a different set of nodes */
static void mpol_rebind_policy(struct mempolicy *pol,
const nodemask_t *newmask)
{
nodemask_t tmp;
int static_nodes;
int relative_nodes;

if (!pol)
return;
static_nodes = pol->flags & MPOL_F_STATIC_NODES;
relative_nodes = pol->flags & MPOL_F_RELATIVE_NODES;
if (!mpol_store_user_nodemask(pol) &&
nodes_equal(pol->w.cpuset_mems_allowed, *newmask))
return;

switch (pol->policy) {
case MPOL_DEFAULT:
break;
case MPOL_BIND:
/* Fall through */
case MPOL_INTERLEAVE:
if (static_nodes)
nodes_and(tmp, pol->w.user_nodemask, *newmask);
else if (relative_nodes)
mpol_relative_nodemask(&tmp, &pol->w.user_nodemask,
newmask);
else {
nodes_remap(tmp, pol->v.nodes,
pol->w.cpuset_mems_allowed, *newmask);
pol->w.cpuset_mems_allowed = *newmask;
}
pol->v.nodes = tmp;
if (!node_isset(current->il_next, tmp)) {
current->il_next = next_node(current->il_next, tmp);
if (current->il_next >= MAX_NUMNODES)
current->il_next = first_node(tmp);
if (current->il_next >= MAX_NUMNODES)
current->il_next = numa_node_id();
}
break;
case MPOL_PREFERRED:
if (static_nodes) {
int node = first_node(pol->w.user_nodemask);

if (node_isset(node, *newmask))
pol->v.preferred_node = node;
else
pol->v.preferred_node = -1;
} else if (relative_nodes) {
mpol_relative_nodemask(&tmp, &pol->w.user_nodemask,
newmask);
pol->v.preferred_node = first_node(tmp);
} else {
pol->v.preferred_node = node_remap(pol->v.preferred_node,
pol->w.cpuset_mems_allowed, *newmask);
pol->w.cpuset_mems_allowed = *newmask;
}
break;
default:
BUG();
break;
}
mpol_ops[pol->policy].rebind(pol, newmask);
}

/*
Expand Down Expand Up @@ -291,6 +321,24 @@ void mpol_rebind_mm(struct mm_struct *mm, nodemask_t *new)
up_write(&mm->mmap_sem);
}

static const struct mempolicy_operations mpol_ops[MPOL_MAX] = {
[MPOL_DEFAULT] = {
.rebind = mpol_rebind_default,
},
[MPOL_INTERLEAVE] = {
.create = mpol_new_interleave,
.rebind = mpol_rebind_nodemask,
},
[MPOL_PREFERRED] = {
.create = mpol_new_preferred,
.rebind = mpol_rebind_preferred,
},
[MPOL_BIND] = {
.create = mpol_new_bind,
.rebind = mpol_rebind_nodemask,
},
};

static void gather_stats(struct page *, void *, int pte_dirty);
static void migrate_page_add(struct page *page, struct list_head *pagelist,
unsigned long flags);
Expand Down Expand Up @@ -1848,7 +1896,6 @@ void numa_default_policy(void)
/*
* Display pages allocated per node and memory policy via /proc.
*/

static const char * const policy_types[] =
{ "default", "prefer", "bind", "interleave" };

Expand Down

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